1. Field of the Invention
The present invention relates to a transmitting receiving earset and more particularly, to an interference-free transmitting receiving earset
2. Description of the Related Art
FIG. 13 shows a conventional transmitting receiving earset 5 for use with a cellular telephone B. According to this design, the transmitting receiving earset 5 comprises a speaker 51 and a microphone 52. According to this design, the microphone 52 is kept at a distance away from the speaker 51. During communication, the microphone 52 picks up the user's voice and the surrounding noises, lowering the communication quality.
FIG. 14 shows an earset for wireless communication according to the prior art. According to this design, the earset 6 comprises an elongated housing 61, a speaker 62 installed in one end of the housing 61, a microphone 63 installed in the other end of the housing 61, and an ear hook 64 connected to the housing 61 for securing the housing 61 to the user's ear. This design of earset 6 cannot eliminate interference of external noises.
U.S. Pat. No. 5,909,498 discloses a transducer device, which includes a pair of transducers in the form of a speaker element and a microphone element mounted in a common housing. According to this design, the speaker element is directed to face the external auditory canal, and the microphone element is positioned in the housing with the receiving side directed toward the outside of the housing. Further, a plate is interposed between the speaker element and the microphone element for isolation to avoid feedback, i.e., audio coupling. Structurally, the housing houses the speaker element and the microphone element. Actually, the microphone element is adapted to receive voices directly from the user's mouth. Sound waves pass from the user's mouth through the air and the rear side of the housing to the microphone element for further transmission to communication apparatus. The microphone element is not kept inside the user's external auditory canal and blocked therein after insertion of the transducer device into the user's ear. Therefore, this design of transducer device cannot eliminate the microphone element from receiving external noises produced by surrounding workplaces, factories, and motor vehicles. During communication through the transducer device, surrounding noises are simultaneously received by the microphone element and transmitted with the user's voice to the remote communication apparatus, thereby causing the person at the remote side cannot hear the voice of the user of the transducer device clearly. Further, because the microphone element is positioned in the rear side of the housing with the receiving side of the microphone element hidden inside the housing, the voice receiving effect of the microphone element is lowered, thereby affecting the communication quality. U.S. Pat. No. 5,909,498 also discloses one alternate form in which the housing has two separated chambers for accommodating the microphone element and the speaker element, a sound passage, and separating means that separates the sound passage into two parallel sound passages for the speaker element and the microphone element respectively. According to this design, the speaker element and the microphone element are positioned in the house in a close manner. Sound waves from the speaker element will be transmitted through the housing to the microphone element, thereby causing the microphone to pick up noises and to transmit the noises to the communication apparatus at the remote side. Further, because the output port of the sound passage for microphone and the output port of the sound passage for speaker are arranged close to each other. Sound waves that pass out of the output port of the sound passage for speaker will partially pass into the output port of the sound passage for microphone and then guided by the sound passage for microphone to the microphone, causing the microphone to transmit the feedback sound waves. Thus, the voice of the person at the remote side will be transmitted to the microphone again, and the microphone will transmit the feedback noises and the voice of the user of the transducer device to the person at the remote side. At this time, the person at the remote side will hear the feedback sound. The interference of the feedback noises greatly affects the communication quality.
U.S. Pat. No. 5,363,444 and U.S. Pat. No. 5,844,984 show another two different designs. According to these two designs, the microphone is positioned on the outside of the housing for picking up the user's voice. During communication, the microphone picks up the user's voice as well as surrounding noises from surrounding workplaces, factories and motor vehicles. Because the user's voice and surrounding noises are transmitted to the remote side, the person at the remote side may be unable to hear the voice of the person at the proximity side. Further, because the microphone is provided at the outside of the housing, it is not kept close to the user's mouth. Therefore, the transmitting quality is poor.